A new family of glass/polymer alloy materials was discovered and described in U.S. Pat. No. 5,043,369 (Bahn et al.). As explained therein, alloy articles consist essentially of an inorganic oxide glass, preferably a phosphate-based glass, and an organic thermoplastic or thermosetting polymer having a working temperature compatible with that of the glass. The low temperature phosphate glass is "melt mixed" with the polymer at the working temperature to form an intimate mixture; i.e., the glass and the polymer are both in a sufficiently fluid state to be blended together to yield a body exhibiting an essentially uniform, fine-grained microstructure.
Once melt-mixed the materials are then extruded through dies and the so-formed raw material strand is then cut into pellets of the desired size. Thereafter, the raw material glass/polymer pellets are then used in injection molding processes to form the desired final product. Conventional wisdom in the plastic processing technology taught the cutting of the extruded strand in its cooled form; based in part on the fact that the molten strand typically stuck to the metal of the cutting tool utilized, whether it be a roller or a cutting wheel. This practice of cutting the so-formed strand in its cooled form was standard in the polymer industry and, therefore it was utilized in the formation of glass/polymer alloy pellets; however, the pellets which resulted were of poor quality. As a result of the lowered ductility of the cooled phosphate glass/polymer strand, when compared to standard cooled plastic strand, the pellets were formed as result of a fracture mechanism of the strand. Thus, the so-formed glass/polymer pellets exhibited irregular shapes and poor flow in addition to being dusty as a result of the high percentage of fines produced. Due to the fact that these fines were subsequently sieved and discarded, the process of cutting the so-formed glass/polymer strand in its cooled state exhibited a very poor yield, on the order of approximately 65-85%. Finally, this method resulted in pellets which exhibited a poor strength and thus additional fines were produced in handling the material. These fines so-produced caused a contamination problem for injection molders as they built up static charges during conveyance by sticking in hoppers and vacuum transfer lines.
As a result of this poor pellet quality and subsequent contamination problem, a better method for producing glass/polymer alloy pellets was therefore sought.